ALARMED: Adverse Events in Low-risk Patients with Chest Pain Receiving Continuous Electrocardiographic Monitoring in the Emergency Department. A Pilot Study

Objectives: Current guidelines suggest that most patients who present to an emergency department (ED) with chest pain should be placed on a continuous electrocardiographic monitoring (CEM) device. We evaluated the utility of CEM in ED patients with chest pain.

Methods: We enrolled stable patients who presented to a single ED with chest pain suspected to be ischemic in origin and who were placed on CEM. Patients were classified according to risk of poor outcome using 3 published stratification tools. Trained observers prospectively recorded number of monitored hours, alarms, changes in management, and monitor-detected adverse events (AEs). The primary outcome measure was the rate of AEs detected by CEM. Secondary outcome measures were the rate of alarms that resulted in a change in management and number of false alarms.

Results: We enrolled 72 patients, 56% of whom were categorized as very low-risk by Goldman risk criteria. During 371 monitored hours, we recorded 1762 alarms or 4.7 alarms per monitored hour. There were 11 AEs (0.68%; 95% CI, 0.35%-1.2%), 3 of which resulted in a change in management (0.2%; 95% CI, 0.04%-0.5%). Seven AEs were bradydysrhythmias with a heart rate of 45 or higher; the eighth patient had no change in symptoms and was given atropine for a heart rate of 32. The other 3 AEs were an untreated supraventricular tachycardia, a brief sinus pause that triggered a rate change in intravenous nitroglycerin by the patient's nurse, and a run of premature ventricular contractions after which heparin was administered. None of the 3 patients with a change in management was categorized as the lowest-risk.

Conclusions: Routine CEM in low-risk ED patients with chest pain results in an excessive number of alarms, most of which require no change in management. In these patients, the benefit of CEM may be limited, and given that 99.4% of alarms were false, current CEM technology needs to be improved.